Ecology

All Materials Cmassengale 

Ecology is the study of interactions between organisms (biotic part) and their nonliving environment (abiotic factors)

Biotic factors includes plants, animals, fungi, & microorganisms. They may be producers, consumers, or decomposers.

Abiotic factors include climate, soil, temperature, water, air, sunlight, humidity, pH, and atmospheric gases.

Habitat is the place a plant or animal lives, while its niche is its total way of life.

Life is organized into levels:

Organism (any single living thing)

            Population (members of the same species living in one place)

 

                    Community (all the populations living in an area)

 

        Ecosystem (community living in a similar habitat such as a forest)

 

Biomes (ecosystems covering wide areas & with similar climates & organisms)

Biosphere ( all the living & nonliving things on earth)

Producers:

bullet

Make their own food through photosynthesis or chemosynthesis

bullet

Includes plants, algal protists, & some bacteria

Consumers:

bullet

Can't make their own food

bullet

May be herbivores (feed only on plants), carnivores (feed only on animals), or omnivores (feed on plants & animals)

Decomposers:

bullet

Break down dead plants & animals (detritus)

bullet

Recycle nutrients

bullet

Called detritivores

bullet

Include fungi & bacteria

Sunlight is the ultimate energy for all life on earth, but only producers can get their energy directly from the sun.

Energyflowinecosystemimage

Trophic levels are feeding levels of producers & consumers in an ecosystem:

bullet

1st Trophic Level is producers that use sunlight directly

bullet

2nd Trophic Level includes herbivores that feed directly on plants

bullet

Higher Trophic Levels are carnivores feeding on each other

energypyramid

Food chains & food webs:

bullet

Chains show who eats whom in an ecosystem.

bullet

Webs are made up of several food chains.

bullet

Always begin with producers absorbing sunlight.

bullet

Producers store energy in the chemical bonds of the food they make.

bullet

Stored energy is passed to consumers when they eat producers or other consumers.

bullet

Some energy is lost at each trophic level as heat when consumers "burn" food during cellular respiration.

bullet

Both energy & nutrients must move through an ecosystem.

Three main elements that must move through an ecosystem:

bullet

Water

bullet

Carbon

bullet

Nitrogen

Water or Hydrologic Cycle:

bullet

Cells are 70 - 90% water

bullet

Water is needed for metabolic processes

bullet

Water is most important for terrestrial organisms because of desiccation (drying out)

Steps in the water Cycle:

Evaporation                                         Transpiration
(water loss from lakes, rivers, oceans...)          (water loss from plant leaves)

                                       

Condensation
(water vapor forms clouds)

Precipitation
(water returns to earth as sleet, rain, snow...)

Surface Runoff
(returns water to bodies of water or to groundwater)

Carbon Cycle:

bullet

Consists of photosynthesis, cellular respiration, & decomposition

bullet

Begins with producers taking carbon dioxide from the air during photosynthesis

bullet

Carbon dioxide used in cellular respiration

bullet

Decomposing plants and animals return Carbon to the soil

Carbon Cycle Steps:

Plant leaves take carbon dioxide from air

Plants store carbon in carbohydrates or starches
(photosynthesis)

Plants & animals release carbon dioxide back into the air
(cellular respiration)

Decomposers return carbon to environment
(decomposition)

Nitrogen:

bullet

Needed by all organisms

bullet

Used to make proteins & nucleic acids (DNA & RNA)

bullet

Air made up of 80% nitrogen

bullet

Only Cyanobacteria & Rhizobium bacteria can use nitrogen directly from the air (nitrogen fixation)

bullet

Bacteria found in the soil & on the roots of legumes (beans, peas ...)

Steps in the Nitrogen Cycle:

Cyanobacteria & Rhizobium take nitrogen from air
(nitrogen fixation)

Convert nitrogen gas into ammonia

Nitrifying bacteria in soil change ammonia into nitrates

Plants can absorb & use nitrates to make proteins

Consumers eat plants & get proteins containing nitrogen

Decomposers break down dead organisms & return nitrogen to air
(called ammonification)

Anaerobic bacteria in soil release nitrogen from nitrates into air
(called denitrification)

Three main types of ecosystems:

bullet

Terrestrial (land)

bullet

Freshwater (rivers, ponds, lakes ...)

bullet

Marine (oceans & seas)

Terrestrial ecosystems are divided into 7 biomes with similar climates & organisms

Seven Terrestrial Biomes:

bullet

Tropical Rain Forest (jungle)

bullet

Savanna (tropical grasslands)

bullet

Deserts

bullet

Grasslands

bullet

Deciduous Forest

bullet

Taiga (coniferous forest)

bullet

Tundra

Tundra:

bullet

Cold & dark most of the year

bullet

Includes the arctic

bullet

Permafrost is the top layer of soil that thaws & in which plants grow

bullet

No trees, but sedges & grass, mosses, & lichens

bullet

Many migratory animals

bullet

Lemmings & ptarmigans are year round residents

bullet

Approximately 20 cm annual rainfall

Tundra

Taiga:

Coniferous Forest

Temperate Deciduous Forest:

Temperate Deciduous Forest

    Tropical Rain forest:

Rainforest

Grasslands:

Grassland

Savanna:

(26KB)

Deserts:

Desert

Aquatic Biomes:

Lakes & Rivers:

Ocean Zones:

BACK